On Monday, Mahamud Said Omar will become the third Minnesotan to stand trial for aiding terrorists in Somalia in a case that gives the closest look yet at a worldwide terror investigation.

The government's case against Omar is spelled out in applications to search the computers at University Travel in Minneapolis and a data-storage device in Omar's cellphone, as well as the prosecutors' trial brief, which was filed Friday.

Jurors to be selected in federal court in Minneapolis will see contrasting views of the 46-year-old Somali man who immigrated to Minnesota in 1993.

The 5-foot-4 defendant often appears bewildered or anxious at court appearances. He complains of seeing ghosts and is prone to seizures or fainting spells. Family members insist that he lacks the intellect to play a key role in a terrorism recruiting network, as the government has alleged.

But recent court filings show that the government sees Omar as a more ominous figure.

Michael Cannizzaro Jr., an agent with the FBI's Joint Terrorism Task Force in Minneapolis, describes Omar in sworn statements filed in late August as a duplicitous and well-traveled member of Al-Shabab, an Islamist insurgency group with suspected links to Al-Qaida.

The United States designated Al-Shabab as a terrorist group in February 2008, making it a federal crime to help the organization. Omar was indicted in Minneapolis in August 2009 on five counts of conspiracy and providing material support to terrorists.

Federal officials say more than 20 young men from the United States, most from Minnesota, have traveled to the Horn of Africa since 2007 to fight with Al-Shabab. At least two have died in suicide bombings and others have risen to leadership positions in the organization, Cannizzaro wrote in affidavits to obtain two search warrants.

The "Operation Rhino" investigation so far has resulted in charges against 18 defendants; seven have pleaded guilty, six remain fugitives and are believed to be in Somalia, and seven were never charged because they have either been confirmed dead or are believed to be dead.

Those numbers don't count two women convicted by jurors in Minneapolis last year of providing support to Al-Shabab. The government never linked their fundraising to the recruitment of young Somali immigrants in Minnesota.

The case against Omar

Several of the recruits who have returned to the United States and pleaded guilty are expected to testify that Omar helped them travel and gave them money to buy weapons in Somalia.

Prosecutors say the conspiracy was hatched about five years ago when two recruiters began meeting in secret with three young Somali men at a Twin Cities mosque and elsewhere.

"In these meetings, [the recruiters] talked of the need to fight jihad in order to oust the Ethiopian armed forces from Somalia," prosecutors say in their brief. Somalia and Ethiopia have a longstanding territorial dispute.

Abdifatah Yusuf Isse, Kamal Hassan and Salah Ahmed eventually agreed to travel to Somalia to fight for the Islamic Courts Union or for Al-Shabab, prosecutors say. They say the men knew little or nothing about Al-Shabab at the time.

The men raised money for the trip by falsely claiming it was for charities, and Omar chipped in several hundred dollars, prosecutors say. Omar flew to Somalia, visited an Al-Shabab safe house in Marka, got married and returned to Minneapolis in April 2008, missing an opportunity to pick up an AK-47 that had been set aside with his name on it.

The Minneapolis men who remained in Somalia received weapons training and helped build a training camp, which prosecutors say was filmed by an Al-Shabab "media crew." Prosecutors plan to show the video to jurors.

Ambushing Ethiopian troops

Prosecutors say they expect to call about 25 witnesses. According to the FBI, one witness reported that in early August 2008, Omar accompanied two young Somali men to the Minneapolis-St. Paul International Airport as they departed for Somalia.

Prosecutors allege that in the summer of 2008, "the conspiracy achieved its object with an ambush of Ethiopian troops by the defendant's conspirators from Minneapolis, together with senior members of [Al-Shabab]." Prosecutors say they plan to show jurors an Al-Shabab "propaganda" video of the ambush.

Prosecutors also will connect Omar with Somali men from the Twin Cities who participated in suicide bombings, particularly in five coordinated truck bombs in Somali territories on Oct. 29, 2008, and an attack on the airport in Mogadishu on Sept. 9, 2010. One of the 2008 terrorists, Shirwa Ahmed of Minneapolis, was said to be the first American suicide bomber.

Within days of the 2008 bombings, prosecutors say, Omar helped six other Twin Cities men leave for Somalia. All eventually joined Al-Shabab, the FBI says. Of those, Jamal Aweys Sheikh Bana and Troy Matthew Kastigar were killed in 2009.

Bid for Dutch asylum

In November 2008, Omar traveled to Saudi Arabia on a pilgrimage, the FBI says. On his return trip to the Twin Cities, he stopped in Amsterdam, destroyed his Somali passport and U.S. residency document and filed for asylum. He was arrested a year later by Dutch authorities at the request of the United States.

In an initial interview with the FBI and Dutch police in 2009, Omar said he had met several of the men who later joined Al-Shabab by chance at University Travel in Minneapolis. He said he drove Sheikh Bana to a bank to withdraw $3,000 in student financial aid money to pay for a "vacation."

The FBI says that Omar admitted to staying at an Al-Shabab safe house in Somalia along with some other Minnesota men. He complained that he was sick when the FBI interview was scheduled to resume and no other interviews took place until June 2011.

While in prison in the Netherlands pending extradition, Omar made a potential plea offer, court filings say. In it, the FBI says Omar admitted that he had met five of the six Al-Shabab recruits at the Minneapolis travel agency knowing they had plans to go fight in Somalia.

The plea deal fell apart and Omar was extradited to Minnesota, where he remains jailed awaiting trial. Prosecutors filed a motion under seal seeking permission to make "unfettered use of the proffer statements at trial," arguing that Omar "egregiously" breached the deal by lying repeatedly. Over the objections of Omar's attorneys, Chief U.S. District Judge Michael Davis ruled that the prosecutors could use the statements, according to the prosecutors' trial brief.